CN205179362U - Single directional MEMS microphone - Google Patents

Abstract

The utility model relates to a unidirectional MEMS microphone. The unidirectional MEMS microphone comprises: a PCB board, on which a first sound hole and a second sound hole are arranged on the PCB; a housing, on which the housing is arranged on the PCB, and the housing is formed with the PCB board accommodating chamber, the first sound hole communicates the accommodating chamber with the outside world, the second sound hole is located outside the accommodating chamber, and a third sound hole is provided on the housing; sound channel, the sound channel It is arranged outside the accommodating chamber, and the sound channel connects the second sound hole with the third sound hole; the MEMS chip and the AISC chip arranged in the accommodating chamber. One purpose of the utility model is to provide a MEMS microphone with unidirectionality.

Description

Unidirectional MEMS Microphone

technical field

The utility model belongs to the technical field of acoustic-electric energy conversion, in particular, the utility model relates to a unidirectional MEMS microphone.

Background technique

Consumer electronics have become an indispensable device in modern life, and people use consumer electronics more and more frequently. Among them, the microphone is used to convert sound into electrical signals, and is an important component of electronic products such as mobile phones. At this stage, MEMS (micro electromechanical system) microphones are mainly used as acoustic-electric transducers in some electronic products.

A MEMS microphone usually includes a MEMS chip and an ASIC chip. Sound waves are transmitted into the MEMS chip from the sound hole on the housing or the PCB board. The diaphragm of the MEMS chip vibrates under the action of the sound waves, thereby converting the sound into an electrical signal. The ASIC chip plays the role of amplifying the signal, amplifying the electrical signal generated by the MEMS chip to facilitate transmission.

As electronic products such as mobile phones are used more and more frequently, and the surrounding environment is becoming more and more complex, correspondingly, the performance defects of traditional MEMS microphones are reflected. For example, when a user is talking on a mobile phone in a noisy environment, the MEMS microphone will pick up all the sound and convert it into an electrical signal. As a result, the other party on the call will hear a lot of noise and cannot accurately identify the user's speech.

Therefore, it is necessary to improve the MEMS microphone so that it can filter out noise or not receive sounds from other directions, thereby improving user experience.

Utility model content

An object of the present utility model is to provide a MEMS microphone with unidirectionality.

According to one aspect of the present utility model, a kind of unidirectional MEMS microphone is provided, comprising:

A PCB board, the PCB board is provided with a first sound hole and a second sound hole;

A casing, the casing is arranged on the PCB board, the casing and the PCB board form an accommodating chamber, the first sound hole communicates the accommodating chamber with the outside world, and the second sound hole is located on the Outside the accommodation cavity, a third acoustic hole is arranged on the housing;

a sound channel, the sound channel is arranged outside the accommodating cavity, and the sound channel connects the second sound hole with the third sound hole;

A MEMS chip AISC chip arranged in the cavity.

Optionally, the unidirectional MEMS microphone includes a shell, the shell is covered on the second sound hole and the third sound hole, and the shell is combined with the outer surface of the housing and the PCB board to surround Form the vocal tract.

Optionally, the unidirectional MEMS microphone includes a casing, the sound channel is formed in the casing, and two ends of the sound channel are connected to the second sound hole and the third sound hole respectively.

Optionally, the sound channel is integrated with the housing, and when the housing is arranged on the PCB, the sound channel is connected to the second sound hole.

Preferably, the second sound hole is provided with a second damping structure. Optionally, a dustproof net may be provided outside the first sound hole.

In particular, a first damping structure is provided outside the first sound hole, and the air permeability of the first damping structure is greater than that of the second damping structure.

Optionally, the third sound hole is disposed on the top or side wall of the casing, and the sound channel extends from the top surface or the side wall of the casing to the PCB.

Preferably, the sound channel is "L" shaped.

Preferably, the casing is a rubber casing.

A technical effect of the utility model is that the unidirectional MEMS microphone can reduce the sound pressure of the incoming sound from the second sound hole, and increase the sound pressure of the sound reaching the diaphragm of the MEMS chip through the first and second sound holes. The distance difference makes the MEMS microphone unidirectional.

Other features and advantages of the present invention will become clear through the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings.

Description of drawings

The accompanying drawings, which constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.

Fig. 1 is a side sectional view of a unidirectional MEMS microphone provided by a specific embodiment of the present invention.

detailed description

Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangements of components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.

The following description of at least one exemplary embodiment is merely illustrative in nature, and in no way serves as any limitation of the invention and its application or use.

Techniques and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such techniques and devices should be considered part of the description.

In all examples shown and discussed herein, any specific values should be construed as exemplary only, and not as limitations. Therefore, other instances of the exemplary embodiment may have different values.

It should be noted that like numerals and letters denote like items in the following figures, therefore, once an item is defined in one figure, it does not require further discussion in subsequent figures.

The utility model provides a unidirectional MEMS microphone, which comprises a PCB board, a casing, a sound channel, a MEMS chip and an ASIC chip. As shown in FIG. 1 , the PCB board 1 is a substrate of a MEMS microphone, on which a first sound hole 11 and a second sound hole 12 are arranged. The housing 2 is disposed on the PCB 1 , and the housing 2 and the PCB 1 form a substantially closed receiving cavity 3 . The first sound hole 11 communicates the accommodating cavity 3 with the outside world, so the second sound hole 12 is located outside the accommodating cavity 3 . In particular, the housing 2 is also provided with a third sound hole 21, and the sound channel 4 is a channel structure located outside the accommodating cavity 3, and the sound channel 4 connects the third sound hole 21 with the The second sound hole 12 is connected. The accommodating cavity 3 passes through the third sound hole 21 and the sound channel 4 , and communicates with the outside from the second sound hole 12 . The MEMS chip 5 is arranged in the accommodating cavity 3 , and generally, the MEMS chip 5 is arranged on the PCB board 1 opposite to the first acoustic hole 11 . As shown in FIG. 1 , the unidirectional MEMS microphone further includes an ASIC chip 6 . The ASIC chip 6 is arranged on the PCB 1 and is mainly used to amplify the electrical signal generated by the MEMS chip. In this way, there are two sound holes in the unidirectional MEMS microphone provided by the utility model, the first sound hole 11 is facing the MEMS chip 5, the first sound hole 11 is the main sound hole, and the accommodating cavity 3 passes through the The sound channel 4 communicates with the outside world through the second sound hole 12, and the second sound hole 12 is used as an infrasound hole.

When the MEMS microphone of the utility model is working, part of the external sound is transmitted from the first sound hole 11 as the main sound hole to one side of the MEMS chip 5, and acts on the diaphragm of the MEMS chip 5 from one side. Other sounds enter the sound channel 4 from the second sound hole 12 as a subsound hole, and pass through the sound channel 4 and the third sound hole 21 into the accommodating cavity 3, and then from the other side of the MEMS chip 5 to the sound channel 4. The diaphragm of the MEMS chip 5 works. That is to say, external sound acts on both sides of the diaphragm in the MEMS chip 5 through the main sound hole and the subsound hole respectively. The sound channel 4 can reduce the sound pressure of the sound transmitted from the infrasound hole to the accommodation cavity 3, and increase the sound path difference between the sound passing through the main and infrasound holes to the diaphragm of the MEMS chip 5 in terms of physical structure. Under the action of channel 4, the MEMS chip has a difference in response sensitivity to the sound incoming from the main sound hole and the subsound hole, thereby realizing the unidirectionality of the MEMS microphone.

Preferably, as shown in FIG. 1, a second damping structure 121 may be provided on the second sound hole 12, and the second damping structure 121 can reduce the ventilation volume of the second sound hole 12, thereby effectively reducing the 12 (infrasound hole) The sound pressure of the sound introduced into the accommodation cavity 3 . The second damping structure 121 cooperates with the sound channel 4 to further increase the sound path difference of the sound transmitted to both sides of the MEMS chip 5 . When sound is transmitted into the MEMS chip 5 from different sound holes, the sensitivity of the diaphragm of the MEMS chip 5 will produce obvious differences. If the main sound hole and the sub-sound hole are directed to different sound source directions, the MEMS microphone will have obvious unidirectionality to the sound in different directions, and have good response sensitivity to the sound from the main sound hole direction, while for Sound from the direction of the subsonic hole has a lower response sensitivity. Those skilled in the art can adjust the air permeability of the second damping structure according to actual performance requirements, so as to achieve the ideal unidirectional effect.

The present invention does not limit the way of forming the sound channel, and those skilled in the art can choose the method of forming the sound channel according to factors such as molding process and performance requirements. In one embodiment of the present utility model, as shown in FIG. 1 , the unidirectional MEMS microphone may include a shell 7, and the shell 7 covers the second sound hole 12 and the third sound hole 21 , the shell 7 is combined with the outer surface of the housing 2 and the PCB 1 to form the sound channel 4 . The casing 7 should have a partially recessed space for forming the sound channel 4 . When the third sound hole 21 is located at the top of the housing 2 , as shown in FIG. 1 , the casing 7 can cover the housing 2 . In this embodiment, the molding process of the sound channel is relatively simple, which facilitates assembly. In another embodiment of the present utility model, the unidirectional MEMS microphone also includes a shell 7, and the channel structure as the sound channel 4 can be directly formed in the shell 7, when the shell 7 is arranged on When the PCB board 1 and the housing 2 are on, the two ends of the channel structure are connected to the second sound hole 12 and the third sound hole 21 respectively. In this embodiment, since the sound channel is completely formed in the shell, the molding process is relatively complicated, but the shape and size of the sound channel are not limited by the shape of the shell, and those skilled in the art can make the sound channel The road is designed into a better structure. Preferably, the shell 7 may be a rubber sleeve, and the structure of the rubber sleeve is easy to form and can form an ideal sound channel structure. Alternatively, the shell 7 may also be a plastic shell or a metal shell, which is not limited by the present invention. In the third embodiment of the present utility model, the sound channel 4 can also be directly formed on the housing 2 , that is, the sound channel 4 and the housing 2 are integrally structured. For example, outside the accommodating cavity 3, the housing 2 also includes a channel structure communicating with the third sound hole 21, and the channel structure serves as the sound channel 4. When the housing 2 is arranged on the PCB board 1, the channel structure is docked with the second sound hole 12 on the PCB 1. In this embodiment, the unidirectional MEMS microphone has fewer parts and is easy to assemble, but the molding process is relatively complicated.

On the other hand, the present invention does not limit the position of the third sound hole on the housing, and those skilled in the art can adjust the position of the third sound hole 21 according to the performance requirements of the unidirectional MEMS microphone. location design. For example, in one embodiment, as shown in FIG. 1 , the third sound hole 21 can be arranged on the top of the housing 2, so that the sound channel 4 should pass from the top surface of the housing 2 extending all the way to the surface of the PCB board 1 . When the unidirectional MEMS microphone includes a shell 7 , the shell 7 can cover the top of the housing 2 , or cover the entire housing 2 . In this embodiment, the sound channel 4 is generally long and has at least a bent portion. In another embodiment, the third sound hole 21 can be arranged on the side wall of the housing 2, and the sound channel 4 extends from the side wall of the housing 2 to the PCB board 1 on the surface. When the unidirectional MEMS microphone includes a shell 7 , the shell 7 may only cover the side wall of the housing 2 . In this embodiment, the length of the vocal tract is generally short.

Further, in the embodiment of the present utility model, the structural shape of the sound channel 4 can also be adjusted according to the performance requirements of the unidirectional MEMS microphone. For example, in the embodiment shown in FIG. 1 , the sound channel 4 extends from the top of the housing 2 to the surface of the PCB 1 , and is in an "L" shape as a whole. In other embodiments, those skilled in the art can adjust the length of the sound channel by adjusting the shape of the sound channel, and the width and diameter of the sound channel also have a direct impact on the directivity performance of the microphone. Those skilled in the art can also design according to actual conditions.

In addition, since the accommodation cavity 3 is directly connected to the outside through the first acoustic hole 11 , external dust may enter the accommodation cavity 3 and the MEMS chip 5 through the first acoustic hole 11 . The entry of foreign matter such as dust and particles will seriously affect the performance of the MEMS chip 5 , so a dust-proof net 111 can be provided outside the first sound hole 11 to prevent dust from entering through the first sound hole 11 . Alternatively, in the case of some special performance requirements or restrictions in the use environment, a first damping structure may be provided outside the first sound hole 11, and the first damping structure is used to reduce the 3 and the sound pressure of the sound of the MEMS chip 5 . In particular, the air flow rate of the first damping structure should generally be greater than the air flow rate of the second damping structure, so that the MEMS chip has a more sensitive response to the sound introduced from the first sound hole.

Although some specific embodiments of the present utility model have been described in detail through examples, those skilled in the art should understand that the above examples are only for illustration, rather than limiting the scope of the present utility model. It should be understood by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the present invention. The scope of the invention is defined by the appended claims.

Claims (10)

1. list points to a MEMS microphone, it is characterized in that, comprising:

Pcb board (1), described pcb board (1) is provided with the first acoustic aperture (11) and the second acoustic aperture (12);

Housing (2), described housing (2) is arranged on described pcb board (1), described housing (2) and pcb board (1) form container cavity (3), described container cavity (3) is in communication with the outside by described first acoustic aperture (11), described second acoustic aperture (12) is positioned at described container cavity (3) outward, described housing (2) is provided with the 3rd acoustic aperture (21);

Sound channel (4), described sound channel (4) is arranged on outside described container cavity (3), and described second acoustic aperture (12) is communicated with the 3rd acoustic aperture (21) by described sound channel (4);

Be arranged on the MEMS chip (5) in described container cavity (3) and AISC chip (6).

2. list according to claim 1 points to MEMS microphone, it is characterized in that, described single MEMS microphone of pointing to comprises valve jacket (7), described valve jacket (7) covers in described second acoustic aperture (12) and the 3rd acoustic aperture (21), and the outer surface of described valve jacket (7) and described housing (2) and pcb board (1) combine to surround and form described sound channel (4).

3. list according to claim 1 points to MEMS microphone, it is characterized in that, described single MEMS microphone of pointing to comprises valve jacket (7), described sound channel (4) is formed in described valve jacket (7), and the two ends of described sound channel (4) are docked with described second acoustic aperture (12) and the 3rd acoustic aperture (21) respectively.

4. list according to claim 1 points to MEMS microphone, it is characterized in that, described sound channel (4) and described housing (2) are structure as a whole, when described housing (2) is arranged on described pcb board (1), described sound channel (4) is docked with described second acoustic aperture (12).

5. list according to claim 1 points to MEMS microphone, it is characterized in that, described second acoustic aperture (12) is provided with the second damping structure (121).

6. point to MEMS microphone according to one of any described list of claim 1-5, it is characterized in that, described first acoustic aperture (11) arranged outside has Air Filter (111).

7. list according to claim 5 points to MEMS microphone, it is characterized in that, described first acoustic aperture (11) arranged outside has the first damping structure, and the Air permenbility of described first damping structure is greater than the Air permenbility of described second damping structure (121).

8. list according to claim 1 points to MEMS microphone, it is characterized in that, on the top that described 3rd acoustic aperture (21) is arranged on described housing (2) or sidewall, described sound channel (4) extends to described pcb board (1) from the end face of described housing (2) or sidewall.

9. list according to claim 1 points to MEMS microphone, it is characterized in that, described sound channel (4) is in " L " type.

10. the list according to Claims 2 or 3 points to MEMS microphone, and it is characterized in that, described valve jacket (7) is gum cover.